154 THE CRYSTAL FALLS IRON-BE ARING UISTRIOT. 



two essential features of strength and durability. For trimming in contrast 

 with lighter stones they might be found desirable, and it may be suggested 

 that they are especially suitable for mosaics in which rich greens are 

 desired. They are of too somber a color to be used in large quantity for 

 anvthing else than foundations. Moreover, the difficulty and consequent 

 expense of quarrying them, and their remoteness from cities of large size, 

 will operate strongly against their use. 



The pyroclastics are natural mosaics, and some of them have a very 

 pleasing appearance (PI. XIII) and are suitable for table tops, wains- 

 coting, etc. 



ROAD MATERIALS. 



The importance of good roads in aiding in the material development 

 of a region can hardly be overestimated, and in the building of good roads, 

 especially in thinly inhabited regions, the proximity of good road material 

 is of prime importance. 



Thus far the 15 miles of good road between Crystal Falls and the 

 adjacent mining villages have been covered with the ferruginous chert and 

 slates from the dumps of the mines, and unroll themselves to the traveler 

 like red ribbons laid through the green woods. 



No rock is better suited for iise in building macadamized roads than 

 the basalt, and of this the Hemlock formation offers an inexhaustible 

 supply. The fine-grained compact basalts are by far the best rocks 

 obtainable, and, other things being equal, should of course be chosen 

 rather than the scoriaceous and consequently weaker facies, but these 

 weaker kinds and also the pyroclastics are preferable to the cherts and 

 slates which have been used. The cherts are very hard and durable, but 

 the dust and sand from them possess but slight capacity for cementation. 

 Consequently the roadways upon which quartzite and chert have been used 

 are more likely to wash out than are the roads macadamized with basalt, 

 since the dust in this latter case serves as a cement which binds the larger 

 fragments more firmly together. The road commissioners have thus far 

 used very little basalt, chiefly for the reasons that no crusher was at their 

 disposal, and the chert and slates were at hand ready for use. 



